SIGNIFICANT ACCOUNTING MATTERS - Reconciliation of Cash (Details) - USD ($) $ in Millions |
Jun. 30, 2025 |
Dec. 31, 2024 |
Jun. 30, 2024 |
Dec. 31, 2023 |
|---|---|---|---|---|
| Significant Accounting Matters [Line Items] | ||||
| Cash and Cash Equivalents | $ 227.3 | $ 202.9 | ||
| Restricted Cash | 51.3 | 43.1 | ||
| Total Cash, Cash Equivalents and Restricted Cash | 278.6 | 246.0 | $ 247.9 | $ 379.0 |
| AEP Texas | ||||
| Significant Accounting Matters [Line Items] | ||||
| Cash and Cash Equivalents | 0.1 | 0.1 | ||
| Restricted Cash | 13.3 | 23.5 | ||
| Total Cash, Cash Equivalents and Restricted Cash | 13.4 | 23.6 | 29.5 | 34.1 |
| APCo | ||||
| Significant Accounting Matters [Line Items] | ||||
| Cash and Cash Equivalents | 6.2 | 3.9 | ||
| Restricted Cash | 18.2 | 16.2 | ||
| Total Cash, Cash Equivalents and Restricted Cash | 24.4 | 20.1 | 19.9 | 19.9 |
| SWEPCo | ||||
| Significant Accounting Matters [Line Items] | ||||
| Cash and Cash Equivalents | 3.7 | 1.2 | ||
| Restricted Cash | 16.7 | 3.4 | ||
| Total Cash, Cash Equivalents and Restricted Cash | $ 20.4 | $ 4.6 | $ 2.4 | $ 2.4 |